1. Field of the Invention
The present invention relates to an image processing apparatus adapted to reconstruct original color image data from a color printed matter obtained by printing according to color image data and a method for controlling the image processing apparatus.
2. Description of the Related Art
When color image data is printed to produce a color printed matter, the image quality of this color image data changes (degrades in most cases) during the printing process.
In fact, when color image data produced in a color gamut of an expanded RGB color space is printed, the color gamut of the color image on the printed matter is compressed to an RGB space within which a printing apparatus is capable of representing colors (that is, degradation in color occurs).
In view of the above, Japanese Patent Laid-Open No. 10-126607 discloses a technique for restoring color image data from color printed matter.
More specifically, Japanese Patent Laid-Open No. 10-126607 discloses a method of converting original color image data itself into a bar code and printing the bar code on paper. If this paper is scanned, the original color image data is read from the inside of the bar code and printed.
However, in the method disclosed in Japanese Patent Laid-Open No. 10-126607, it is necessary to convert color image data having a very large amount of information into a bar code. The result is an increase in the size of the bar code (which may be a 1-dimensional or 2-dimensional bar code).
For example, color image data of an image with 6 mega pixels of each of RGB colors taken by a digital camera has a data size of 18 Mbytes, while the data size of a bar code on an A4-size sheet is as small as about 1 Kbytes. The ratio is as great as 18000:1.
Thus, there is a need for a technique to reproduce beautiful color image data from a printed matter produced by printing the color image data and digital watermark image data in which information with low information content is embedded.